The Quiver of One Wheelset: Why we should move toward the boost 148 spacing for gravel.
If you own a late model cx or mountain bike you could have any of the following rear hub standards: 130 x 9 QR, 135 x 9 QR, 135 x 9 TA, 135 x 12 TA, 142 x 12 TA or 148 x 12... Sigh. Front hubs are slightly, very slightly better coming in at 100 x 9 QR, 100 x 12 TA, 100 x 15 TA and 110 x 15 TA. Ok, catch your breath. That's 10 possible sizes between front and rear. My lack of statistics skills and motivation prevent me from calculating all of the possible combinations that could arise from those variations but suffice to say, it's a bunch! You may be saying to yourself “Who cares”. Well, you do... If you're of limited financial resources and want some sweet new wheels, walk out to your bike, see what it has and order them up. Oh, and then walk over to your other bike, notice the dope wheels you just purchased won't fit... You just spent $1500 to upward of $3000 on a set of wheels that you may only be able to use on one bike. Somethings gotta change!
Well, we had a solution for a hot minute... 100 x 15 front TA and 142 x 12 rear TA. This is all fine and good as many CX, Gravel and mountain bikes share that particular set of axle spacing. Then boost, in all it's glory came along. It promised us stiffer rear wheels and extra tire clearance! For the most part, it has succeeded if not surpassed it's goals. The issue is, mountain bikes have pretty much embarrassed boost spacing yet CX and Gravel have not. Well, why haven't they? Some would suggest that the stiffness and clearance offered by boost isn't needed for cx and gravel. I'm here to tell you, if it's not needed today, it will be soon. That's evidenced by the current trend so stuffing the largest tire possible into gravel bikes. As a frame fabricator, I can tell you a point comes when tire and chainring clearance is minimized based on the width of the rear axle... So, boost to the rescue! The 6 to 18mm (depending on your current set up) could add just enough width at the chainstays to stuff a 2” tire in... Though this isn't as much of an issue with cx, wouldn't it be nice to be able to ride a big fat tire on your cx bike for the one or two gravel races you may do? The front end could become a compatibility issue, cx/gravel have stuck with 100mm spacing (but commonly use three different axles, 9mm QR, 12mm TA or 15mm TA). I'm noticing a trend for cx forks to move toward a 100 x 12mm axle, Perhaps we could get in the manufactures head and let them know about the potential need for a gravel/cx fork that accepted a 110 x 15 axle...
Where am I going with all of this? Here's your point to ponder... Would it be nice to have a Gravel/cx bike that used Boost spacing and had big tire clearance? Imagine being able to tell your significant other that the sweet/awesome carbon, bling bling hub wheels you just dropped 3K on will work on three of your bikes! Gravel, cx and mountain!!! How's that for a selling point? Imagine... three bikes, one wheelset... A boy (or girl) can dream!